Ceramic electronic component and method of manufacturing the same

ABSTRACT

There are provided a ceramic electronic component and a method of manufacturing the same. The ceramic electronic component includes: a ceramic element; and an internal electrode layer formed within the ceramic element, having a thickness of 0.5 μm or less, and including a non-electrode region formed therein, wherein an area ratio of the non-electrode region to an electrode region of the internal electrode layer, in a cross section of the internal electrode layer is between 0.1% and 10%, and the non-electrode region includes a ceramic component.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Korean Patent Application No.10-2011-0088030 filed on Aug. 31, 2011, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a ceramic electronic component and amethod of manufacturing the same, and more particularly, to a ceramicelectronic component having excellent reliability and a method ofmanufacturing the same.

2. Description of the Related Art

In general, an electronic component using a ceramic material, such as acapacitor, an inductor, a piezoelectric element, a varistor, athermistor, or the like, includes a ceramic element made of a ceramicmaterial, internal electrode layers formed within the ceramic element,and external electrodes installed on surfaces of the ceramic element,such that they are connected with respective internal electrode layers.

Among ceramic electronic components, a multilayer ceramic capacitorincludes a plurality of laminated dielectric layers, internal electrodelayers disposed to face each other, while having each of the dielectriclayers interposed therebetween, and external electrodes electricallyconnected with the respective internal electrode layers.

The multilayer ceramic capacitor is commonly used as a component ofmobile communications devices such as notebook computers, PDAs (PersonalDigital Assistants), mobile phones, and the like, due to its advantages,such as miniaturization, high capacitance, and easy mounting.

Recently, as electronic devices have increasingly had higherperformances and have become lighter, thinner, shorter, and smaller,electronic components have also been required to be small, have a highperformance, and incur low manufacturing costs. In particular, thedevelopment of CPUs which have high speeds and devices which are smallerand lighter, digitalized, and multi-functionalized has prompted,research and development aimed at implementing a multilayer ceramiccapacitor which is small, includes thinner layers, has high capacitance,and has low impedance in a high frequency area, and the like have beenactively undertaken.

SUMMARY OF THE INVENTION

An aspect of the present invention provides a ceramic electroniccomponent having excellent reliability and a method of manufacturing thesame.

According to an aspect of the present invention, there is provided aceramic electronic component including: a ceramic element; and aninternal electrode layer formed within the ceramic element, having athickness of 0.5 μm or less, and including a non-electrode region formedtherein, wherein an area ratio of the non-electrode region to anelectrode region of the internal electrode layer, in a cross section ofthe internal electrode layer is between 0.1% and 10%, and thenon-electrode region includes a ceramic component.

A thickness of the internal electrode layer may be 0.5 μm or less.

Connectivity of the internal electrode layer, as defined by a ratio ofan actual length of the internal electrode layer to the total length ofthe internal electrode layer (actual length of the internal electrodelayer:total length of the internal electrode layer), may be 90% or more.

The internal electrode layer may be formed of a conductive pasteincluding metal powder and ceramic-based substance powder whose grainsize ratio to that of the metal powder exceeds 1:5.

The non-electrode region may be formed by firing a conductive pasteforming the internal electrode layer at a heating rate ranging from 30°C./60 s to 50° C./60 s.

According to another aspect of the present invention, there is provideda ceramic electronic component including: a ceramic element including aplurality of dielectric layers laminated therein; and internal electrodelayers having each dielectric layer interposed therebetween, and havinga thickness of 0.5 μm or less, wherein an area ratio of a non-electroderegion trapped in each internal electrode layer to an electrode region,in a cross section of the internal electrode layer is between 0.1% and10%, and connectivity of the inner electrode layer is 90% or more.

The non-electrode region may include ceramic-based substance powderwhose grain size ratio to that of metal powder forming the internalelectrode layer exceeds 1:5.

The internal electrode layer may be formed by adjusting a firingtemperature of a conductive paste including metal powder andceramic-based substance powder.

According to another aspect of the present invention, there is provideda ceramic electronic component including: a ceramic element; and aninternal electrode layer formed within the ceramic element, wherein anarea ratio of a non-electrode region to an electrode region of theinternal electrode layer, in a cross section of the internal electrodelayer is between 0.1% and 10%.

A thickness of the internal electrode layer may be 0.5 μm or less.

Connectivity of the internal electrode layer, as defined by a ratio ofan actual length of the internal electrode layer to the total length ofthe internal electrode layer, may be 90% or more.

The non-electrode region may be trapped at a metal particle interface ofthe internal electrode layer.

The non-electrode region may include ceramic-based substance powder.

The internal electrode layer may be formed of a conductive pasteincluding metal powder and ceramic-based substance powder whose grainsize ratio to that of the metal powder exceeds 1:5.

The non-electrode region may be formed by adjusting a firing temperatureof a conductive paste forming the internal electrode layer.

According to another aspect of the present invention, there is provideda method of manufacturing a ceramic electronic component, the methodincluding:preparing ceramic green sheets; forming internal electrodepatterns with a conductive paste including metal powder andceramic-based substance powder whose grain size ratio to that of themetal powder exceeds 1:5; laminating ceramic green sheets having theinternal electrode patterns formed thereon to form a ceramic laminate;and firing the ceramic laminate to form an internal electrode layer inwhich an area ratio of a non-electrode region to an electrode region isbetween 0.1% and 10%.

The firing of the ceramic laminate may be performed at a heating rate(i.e., a temperature increase rate) ranging from 30° C./60 s to 50°C./60 s.

Sintering of the metal powder included in the conductive paste may berestrained to 1000□.

Connectivity of the inner electrode layer may be 90% or more.

A thickness of the internal electrode layer may be 0.5 μm or less.

The non-electrode region may be trapped in the internal electrode layerduring the firing of the ceramic laminate.

The non-electrode area may include a ceramic component.

The non-electrode region may include a binder or a solvent remainingtherein after the firing.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a schematic perspective view of a multilayer ceramic capacitor(MLCC) according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of the MLCC taken along lineA-A′ in FIG. 1;

FIG. 3 is a schematic partially enlarged view showing a cross section ofthe MLCC according to an embodiment of the present invention;

FIG. 4 is a schematic partially enlarged view showing an internalelectrode layer according to an embodiment of the present invention; and

FIGS. 5A and 5B are schematic views showing a sintering shrinkagebehavior of the internal electrode layer according to an embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the present invention will now be described in detailwith reference to the accompanying drawings. The invention may, however,be embodied in many different forms and should not be construed as beinglimited to the embodiments set forth herein. Rather, these embodimentsare provided so that this disclosure will be thorough and complete, andwill fully convey the scope of the invention to those skilled in theart. In the drawings, the shapes and dimensions may be exaggerated forclarity, and the same reference numerals will be used throughout todesignate the same or like components.

An embodiment of the present invention relates to a ceramic electroniccomponent, and electronic components using a ceramic material mayinclude a capacitor, an inductor, a piezoelectric element, a varistor, athermistor, and the like. Hereinafter, a multilayer ceramic capacitor(MLCC) will be described as an example of the ceramic electroniccomponent.

FIG. 1 is a schematic perspective view of a multilayer ceramic capacitor(MLCC) according to an embodiment of the present invention. FIG. 2 is aschematic cross-sectional view of the MLCC taken along line A-A′ in FIG.1.

With reference to FIGS. 1 and 2, the multilayer ceramic capacitor (MLCC)according to an embodiment of the present invention may include aceramic element 110, internal electrode layers 121 and 122 formed withinthe ceramic element 110, and external electrodes 131 and 132 formed onexternal surfaces of the ceramic element 110.

In an embodiment of the present invention, a ‘length direction’ may bedefined as an ‘L’ direction shown in FIG. 1. Likewise, a ‘widthdirection’ may be defined as a ‘W’ direction and a ‘thickness direction’may be defined as a ‘I’ direction. Here, the ‘thickness direction’ mayhave the same conception as a direction of stacked dielectric layers,that is, a ‘lamination direction.’

The ceramic element 110 may have a hexahedron shape according to anembodiment of the present invention, but the present invention is notlimited thereto.

The ceramic element 110 may be formed by laminating a plurality ofdielectric layers 111. The plurality of dielectric layers 111constituting the ceramic element 110 may be sintered and integrated suchthat boundaries therebetween may not be readily apparent.

The dielectric layers 111 may be formed by sintering ceramic greensheets including ceramic powder.

The ceramic powder is not particularly limited so long as it isgenerally used in the art. The ceramic powder may include, for example,a BaTiO₃-based ceramic powder, but the present invention is not limitedthereto. The BaTiO₃-based ceramic powder may include(Ba_(1-x)Ca_(x))TiO₃, Ba(Ti_(1-y)Ca_(y))O₃, (Ba_(1-x)Ca_(x))(Ti_(1-y)Zr_(y))O₃, Ba(Ti_(1-y)Zr_(y))O₃, or the like, which is formedby partially employing Ca, Zr, or the like in BaTiO₃, but the presentinvention is not limited thereto.

The ceramic green sheets may include a transition metal, a rare earthelement, magnesium (Mg), aluminum (Al), or the like, as well as theceramic powder.

The thickness of each dielectric layer 111 may be appropriately alteredaccording to a capacitance design of the multilayer ceramic capacitor.For example, the thickness of each dielectric layer 111 formed betweentwo internal electrode layers after sintering may be 1.0 μm or less, butthe present invention is not limited thereto.

The internal electrode layers 121 and 122 may be formed within theceramic element 110. The internal electrode layers 121 and 122 may beformed and laminated on the ceramic green sheets. The internal electrodelayers 121 and 122 may have each dielectric layer interposedtherebetween within the ceramic element 110 through sintering.

The internal electrode layers 121 and 122 may be pairs of internalelectrode layers having different polarities and may be disposed to beopposed to each other according to the lamination direction of thedielectric layers.

As shown in FIG. 2, respective ends of the first and second internalelectrode layers 121 and 122 may be alternately exposed to one face ofthe ceramic element 110 in the length direction.

Although not shown, according to an embodiment of the present invention,the first and second internal electrode layers may have respective leadportions and may be exposed to the same face of the ceramic elementthrough the lead portions. Alternatively, the first and second internalelectrode layers may have respective lead portions and be exposed to oneor more faces of the ceramic element through the lead portions.

The thickness of each of the internal electrode layers 121 and 122 maybe appropriately determined according to the intended purpose thereof,or the like. For example, the thickness of each of the internalelectrode layers 121 and 122 may be 0.5 μm or less. Alternatively, thethickness of each of the internal electrode layers 121 and 122 may be0.1 μm to 0.5 μm.

Alternatively, the thickness of each of the internal electrode layers121 and 122 may be 0.3 μm to 0.5 μm.

According to an embodiment of the present invention, 200 or moredielectric layers having the internal electrode layers formedtherebetween may be laminated. The detailed description thereof will bedescribed later.

According to an embodiment of the present invention, the externalelectrodes 131 and 132 may be formed on the external surfaces of theceramic element 110. The external electrodes 131 and 132 may beelectrically connected to the internal electrode layers 121 and 122. Indetail, the external electrodes 131 and 132 may include a first externalelectrode 131 electrically connected to the first internal electrodelayers 121 exposed to one face of the ceramic element 110, and a secondexternal electrode 132 electrically connected to the second internalelectrode layers 122 exposed to the other face of the ceramic element110.

Also, although not shown, a plurality of external electrodes may beformed such that they are connected to the first and second internalelectrode layers exposed to faces of the ceramic element.

The external electrodes 131 and 132 may be formed of a conductive pasteincluding metal powder. As the metal powder included in the conductivepaste, for example, nickel (Ni), copper (Cu), or an alloy thereof may beused, but the present invention is not particularly limited thereto. Thethickness of the external electrodes 131 and 132 may be appropriatelydetermined according to the intended purpose thereof, or the like. Forexample, the thickness of the external electrodes 131 and 132 may be 10μm to 50 μm.

FIG. 3 is a schematic partially enlarged view showing a cross section ofthe MLCC according to an embodiment of the present invention.

With reference to FIG. 3, each of the internal electrode layers 121 and122 according to an embodiment of the present invention may include anon-electrode region N therein. According to an embodiment of thepresent invention, the portion of the internal electrode, excluding thenon-electrode region N, may be understood as an electrode region E.

According to an embodiment of the present invention, the non-electroderegion N may be formed during an internal electrode layer firingprocess. The non-electrode region N may be formed of a composition ofthe conductive paste forming the internal electrode layers. Thenon-electrode region N may include a ceramic component, but the presentinvention is not limited thereto. According to an embodiment of thepresent invention, the non-electrode region N may be formed of acomponent, among components included in the conductive paste, which isnot a conductive metal. For example, the non-electrode region N may bemade of ceramic powder. Also, a material forming the non-electroderegion N may include, for example, a ceramic-based substance powder, abinder, a solvent, or the like. The binder and solvent may exist as acarbon-based component remaining in the non-electrode region throughfiring. Also, the non-electrode region N may be a pore.

According to an embodiment of the present invention, a material includedin the composition of the conductive paste may be trapped at aninterface, i.e., at a grain boundary of metal grains forming theinternal electrode layers during firing. This can be clarified throughthe process of forming the internal electrode layers, to be describedlater.

According to an embodiment of the present invention, an area ratio ofthe non-electrode region N to the electrode region E of the internalelectrode layer, in a cross section of the internal electrode layer maybe between 0.1 and 10%.

As shown in FIG. 2, the multilayer ceramic capacitor may be cut in thelength direction. In the cross section cut in the length direction, thearea of the internal electrode layer, the area of the electrode regionE, and the area of the non-electrode region N may be measured.

In an embodiment of the present invention, the area of the internalelectrode layer, the area of the electrode region E, and the area of thenon-electrode region N may be measured by scanning an image of a crosssection of the multilayer ceramic capacitor through an opticalmicroscope.

The process of measuring the area of the internal electrode layer, thearea of the electrode region E, and the area of the non-electrode regionN will be described with reference to FIGS. 3 and 4.

In an embodiment of the present invention, the area of the internalelectrode layer refers to an area in which the internal electrode layeris continuous, except for a portion in which the internal electrodelayer is disconnected. With reference to FIG. 3, the area of theinternal electrode layer excludes the area of a gap G formed between theseparated portions thereof. In an embodiment of the present invention,the gap G refers to a pore penetrating the internal electrode layer, anddoes not include a pore formed only at a portion of the surface of theinternal electrode layer or formed in the internal electrode layer.

The internal electrode layer and the dielectric layer may bediscriminated from the optical image, and the area of the internalelectrode layer may be measured. The non-electrode region N and theelectrode region E formed in the internal electrode layer may be shownas having different shades so as to be discriminated in the opticalimage. The area of the internal electrode layer, the area of theelectrode region, and the area of the non-electrode region may bemeasured by using a computer program such as SigmaScan Pro, or the like,but the present invention is not limited to being measured thereby.

In an embodiment of the present invention, the area of the electroderegion E may be understood as being obtained by subtracting the area ofthe non-electrode region N from the area of the internal electrodelayer.

According to an embodiment of the present invention, the area ratio ofthe non-electrode region N to the electrode region E of the internalelectrode layer, in the cross section of the internal electrode layercut in the length direction of the multilayer ceramic capacitor may bebetween 0.1% and 10%.

According to an embodiment of the present invention, connectivity of theinternal electrode layer may be 90% or greater by adjusting the arearatio of the non-electrode region N.

According to an embodiment of the present invention, connectivity of theinternal electrode layer may be defined as a ratio of the length ofportions actually forming the internal electrode layer with respect tothe total length of the internal electrode layer (i.e., actual length ofthe internal electrode layer:the total length of the internal electrodelayer).

The total length of the internal electrode layer and the length ofportions actually forming the internal electrode layer may be measuredthrough the use of an optical image obtained by scanning the cut crosssection of the multilayer ceramic capacitor.

In detail, the ratio of the length of portions actually forming theinternal electrode layer with respect to the total length of theinternal electrode layer may be measured from the image obtained byscanning the cross section of the ceramic element in the lengthdirection, which is obtained by cutting the central portion of theceramic element in the width direction.

In an embodiment of the present invention, the total length of theinternal electrode layer may refer to the length including the gap Gformed between the separated portions thereof, in each internalelectrode. The length of portions actually forming the internalelectrode may refer to the length excluding the gap G formed between theseparated portions thereof, in each internal electrode. As describedabove, the gap G refers to a pore penetrating the internal electrodelayer and does not include a pore formed only at a portion of thesurface of the internal electrode layer or formed in the internalelectrode layer.

According to an embodiment of the present invention, as shown in FIG. 4,the total length of the internal electrode layer and the length ofportions actually forming the internal electrode layer may be measuredby taking a portion of the optical image. In detail, when it is assumedthat the total length of the internal electrode layer, as the totallength of the internal electrode layer 121 including pores in somepoints thereof, is T, and the length of portions actually forming theinternal electrode layer are t1, t2, t3, connectivity of the internalelectrode layer may be expressed as (t1+t2+t3+·+tn)/T. In FIG. 4, theportions actually forming the internal electrode layer are expressed ast1, t2, t3 and t4, but the number of portions actually forming theinternal electrode layer is not particularly limited.

According to an embodiment of the present invention, the actual lengthof the internal electrode layer may be measured by subtracting thelength of the gaps G from the total length T of the internal electrodelayer.

According to an embodiment of the present invention, the thickness ofeach of the internal electrode layers 121 and 122 may be 0.5 μm or less.Alternatively, the thickness of each of the internal electrode layers121 and 122 may be 0.1 μm to 0.5 μm. Alternatively, the thickness ofeach of the internal electrode layers 121 and 122 may be 0.3 μm to 0.5μm.

In an embodiment of the present invention, as mentioned above, thethickness of the internal electrode layer may be measured by scanning animage of a cross section of the multilayer ceramic capacitor through theoptical microscope. The thickness of the internal electrode layer may beobtained by taking a portion of the scanned image.

In an embodiment of the present invention, the thickness of the internalelectrode layer may be calculated as a ratio of the area of the internalelectrode layer with respect to the actual length of the internalelectrode layer (internal electrode layer area: actual length of theinternal electrode layer).

The area of the internal electrode layer may refer to the area includingthe electrode region E and the non-electrode region N, and the actuallength of the internal electrode layer may be the length excluding thegap G formed between the separated portions thereof.

According to an embodiment of the present invention, the area of theinternal electrode layer, the area of the electrode region E, the areaof the non-electrode region N, and the actual length of the internalelectrode layer may be measured in each internal electrode layer, andmay be multiplied by the number of laminations thereof so as to begeneralized in terms of the entire multilayer ceramic capacitor.

In the multilayer ceramic capacitor, capacitance may be formed by anoverlapped area of the first and second internal electrodes.

In general, internal electrode layers may be conglomerated to be brokenduring sintering. Then, capacitance formed due to the internal electrodelayers may be reduced and irregularly formed, degrading the reliabilitythereof. Thus, in order to implement high capacitance, securingconnectivity of the internal electrode layer may be required.

However, as the multilayer ceramic capacitor is reduced in size andhighly multilayered, the internal electrode layers become thinner. Asthe internal electrode layers become thinner, the internal electrodelayers may be easily broken during sintering, such that securingconnectivity of the internal electrode layer may be difficult.

However, according to an embodiment of the present invention,connectivity of the internal electrode layer may be secured through theinclusion of the non-electrode region in the internal electrode layer.According to an embodiment of the present invention, thinness of theinternal electrode layer may be compensated for by including thenon-electrode region therein. Also, a disconnection of the internalelectrode layer may be prevented by restraining a firing shrinkage ofthe metal powder during the firing of the internal electrode layer. Whenthe area ratio of the non-electrode region to the electrode region ofthe internal electrode layer is small, it is difficult to secureconnectivity of the internal electrode layer. On the other hand, whenthe area ratio of the non-electrode region to the electrode region ofthe internal electrode layer is extremely large, connectivity of theinternal electrode layer may deteriorate.

FIGS. 5A and 5B are schematic views showing a sintering shrinkagebehavior of the internal electrode layer according to an embodiment ofthe present invention. The present invention will be described withreference to FIGS. 5A and 5B.

According to an embodiment of the present invention, the internalelectrode layer may be made of a conductive paste including metal powder21 and ceramic-based substance powder 22.

According to an embodiment of the present invention, the type of themetal powder 21 forming the internal electrode layer is not particularlylimited. For example, a base metal may be used. Nickel (Ni), manganese(Mn), chromium (Cr), cobalt (Co), aluminum (Al), or an alloy thereof maybe provided, and the metal powder 21 may include at least one amongthem, but the present invention is not limited thereto.

An average grain size of the metal powder 21 is not particularlylimited. For example, the average grain size may be 400 nm or less. Indetail, the average grain size may be 50 nm to 400 nm.

According to an embodiment of the present invention, the ceramic-basedsubstance powder 22 may be the same type as that of as the ceramicpowder 11 forming the dielectric layers. The ceramic-based substancepowder 22 may move from the internal electrode layer to the dielectriclayer during firing, and may be the same type as that of the ceramicpowder forming the dielectric layers in order to prevent degradation incharacteristics of the dielectric layers. The ceramic-based substancepowder 22 may be, for example, a BaTiO₃-based ceramic powder, but thepresent invention is not limited thereto. The BaTiO3-based ceramicpowder may include (Ba_(1-x)Ca_(x)) TiO₃, Ba(Ti_(1-y)Ca_(y))O₃,(Ba_(1-x)Ca_(x)) (Ti_(1-y)Zr_(y))O₃, Ba(Ti_(1-y)Zr_(y))O₃, or the like,which is formed by partially employing Ca, Zr, or the like in BaTiO₃,but the present invention is not limited thereto.

The grain size of the ceramic-based substance powder 22 may be smallerthan that of the metal powder 21. For example, a ratio of the grain sizeof the ceramic-based substance powder 22 to that of the metal powder 21(i.e., ceramic-based substance powder:metal powder) may not exceed 1:5,but the present invention is not limited thereto. Also, according to anembodiment of the present invention, the ratio of the grain size of theceramic-based substance powder 22 to that of the metal powder 21 (i.e.,ceramic-based substance powder:metal powder) may be 1:3 to 1:4.

According to an embodiment of the present invention, each of the grainsize of the metal powder 21 and that of the ceramic-based substancepowder 22 may be an average grain size thereof. According to anembodiment of the present invention, the average grain size of theceramic-based substance powder and the average grain size of the metalpowder may be measured according to an average grain size measurementmethod defined by the ASTM (American Society for Testing and Materials).

According to an embodiment of the present invention, the grain size ofthe ceramic-based substance powder 22 is smaller than that of the metalpowder 21, so that the ceramic-based substance powder 22 may bedistributed between the metal grains of the metal powder 21.

According to an embodiment of the present invention, when the ratio ofthe grain size of the ceramic-based substance powder to that of themetal powder (i.e., ceramic-based substance powder:metal powder) is lessthan 1:5, the ceramic-based substance powder may not be able toeffectively restrain the shrinkage of the metal grains. Theceramic-based substance powder may be disposed between the metal grainsto restrain a grain growth of the metal grains when the metal grains aresintered.

Here, the ceramic-based substance powder, grains of which have a sizesmaller than that of a pore formed during the sintering of the metalgrains, may not limit contact of the metal grains, and may havedifficulty in obstructing the grain growth of the metal grains. Thedetailed description thereof will be described later.

According to an embodiment of the present invention, the composition ofthe conductive paste forming the internal electrode layers may furtherinclude a binder, a solvent, other additive, or the like.

As the binder, polyvinylbutyral, a cellulose-based resin, or the like,may be used, but the present invention is not limited thereto.Polyvinylbutyral having strong adhesion characteristics may enhancebonding strength between the conductive paste and the ceramic greensheet.

The cellulose-based resin, having a chair-type structure, hascharacteristics quickly restored due elasticity when it is deformed.Through the inclusion of the cellulose-based resin, a flat print facemay be secured.

The solvent is not particularly limited. For example, butylcarbitol,kerosene, or a terpineol-based solvent may be used therefor. Specifictypes of the terpineol-based solvent may include dehydro terpineol,dehydro terpineol acetate, or the like, but the present invention is notlimited thereto.

According to an embodiment of the present invention, the composition ofthe conductive paste may be trapped to form the non-electrode region Nin the internal electrode layer, during the firing of the internalelectrode layer.

According to an embodiment of the present invention, a material includedin the composition of the conductive paste may be trapped at theinterface, i.e., the grain boundary, of the metal grains forming theinternal electrode layer during the firing. Also, a pore may be formedat the interface of the metal grains during the firing performed on theinternal electrode layer, and the pore may be formed in the internalelectrode layer while being trapped, unlike the gap G illustrated inFIGS. 3 and 4.

In general, the conductive paste is printed on the ceramic green sheets,the ceramic green sheets having the conductive paste printed thereon maybe laminated, and then the conductive paste may be simultaneously firedtogether with the ceramic green sheets.

Also, in a case in which the internal electrode layer is made of a basemetal, when firing is performed on the internal electrode layer in theatmosphere, the internal electrode layer may be oxidized. Thus, theceramic green sheet and the internal electrode layer may besimultaneously fired under a reduction atmosphere.

The dielectric layers of the multilayer ceramic capacitor may be formedby firing the ceramic green sheets at a high temperature of about 1100␣or higher. When the internal electrode layer is made of a base metalsuch as nickel (Ni), or the like, the oxidization of the internalelectrode layer may start from a temperature of 400□, a relatively lowtemperature, and then the internal electrode layer may be sintered andshrunken and may be rapidly shrunken at 1000□ or higher. When theinternal electrode layer is rapidly fired, the electrode may beconglomerated or broken due to the excessive firing of the internalelectrode layer, and connectivity of internal electrode layer maydeteriorate to degrade the capacitance of the multilayer ceramiccapacitor. Also, after the firing, the multilayer ceramic capacitor mayhave a defective internal structure such as a crack, or the like.

Thus, improvements in connectivity of the internal electrode layerthrough minimizing a shrinkage rate difference between the internalelectrode layer and the dielectric layer by possibly delaying asintering initiation temperature of the metal powder, starting from arelatively low temperature of 400□ to 500□, may be required.

FIG. 5A shows an initial stage of firing before the sintering shrinkageof the metal powder 21 starts, and FIG. 5B schematically shows a statein which the metal powder 21 is sintered and shrunken as temperaturerises.

In FIGS. 5A and 5B, the ceramic powder 11 may form the dielectric layers11 illustrated in FIG. 2 through sintering.

With reference to FIGS. 5A and 5B, the metal powder is shrunken in theinitial stage of firing, and the ceramic-based substance powder 22 maybe disposed between the metal grains of the metal powder to limit thecontact between the metal grains.

In general, before the ceramic powder 11 forming the dielectric layersis shrunken, the metal powder is sintered to form the internal electrodelayer. Thus, the internal electrode layer may be conglomerated when theceramic powder is shrunken, degrading the connectivity of the innerelectrode.

However, according to an embodiment of the present invention, theconnectivity of the inner electrode may be secured by controlling thearea ratio of the non-electrode region within the internal electrodelayer.

According to an embodiment of the present invention, the grain sizeratio of the ceramic-based substance powder 22 may be controlled and thegrains thereof may be distributed between the grains of the metal powder21. Then, sintering of the metal powder 21 may be restrained to about1000□ or higher. The sintering of the metal powder 21 may be restrainedto a certain temperature as much as possible, and the sintering of theceramic powder 11 forming the dielectric layers may be initiated. As thedensification of the ceramic powder 11 forming the dielectric layers isundertaken, the internal electrode layer starts to be densified, rapidlyaccelerating sintering.

According to an embodiment of the present invention, the ceramic-basedsubstance powder 22 may lower the sintering shrinkage initiationtemperature of the metal powder 21 and restrain the sintering shrinkageof the metal powder 22. Since the grain size ratio of the ceramic-basedsubstance powder 22 is controlled, the ceramic-based substance powder 22may prevent the grains of metal powder from coming into contact witheach other when the metal powder is sintered to be shrunken, restraininga grain growth of the metal powder and restraining the internalelectrode from being conglomerated.

According to an embodiment of the present invention, a portion of theceramic-based substance powder 22 may be transferred to the surface ofthe internal electrode layer so as to be sintered together with theceramic powder 11 forming the dielectric layers. However, anotherportion of the ceramic-based substance powder 22 may fail to escape fromthe metal powder 21 until sintering is completed, and thus may betrapped at the grain boundary of the metal grains as shown in FIG. 3.Accordingly, the ceramic-based substance powder may form thenon-electrode region N in the internal electrode layer.

According to an embodiment of the present invention, a portion of theceramic-based substance powder 22 is transferred to the surface of theinternal electrode layer so as to be sintered together with the ceramicpowder 11 forming the dielectric layers. However, when the heating rateof firing is adjusted, another portion of the ceramic-based substancepowder 22 may not escape from the metal powder 21 to be trapped at thegrain boundary of the metal grains as shown in FIG. 3.

According to an embodiment of the present invention, the binder, thesolvent, or other additives included in the composition of theconductive paste forming the internal electrode layers are removedduring the firing. However, when the heating rate of the firing processis adjusted, a part of the binder, the solvent, and other additives maynot be completely removed but may be trapped at the grain boundary ofthe metal grains as shown in FIG. 3. Accordingly, the binder, thesolvent, and other additives may form the non-electrode region N in theinternal electrode layer.

As described above, according to an embodiment of the present invention,the area ratio of the non-electrode region N to the electrode region Eof the internal electrode layer, in a cross section of the internalelectrode layer may be between 0.1% and 10%.

Recently, as multilayer ceramic capacitors have advanced toward having asmall size and light weight, the internal electrode layers thereof arebecoming thinner. In order to thin internal electrode layers, metalpower having small grains may be used, but in this case, it is difficultto control the sintering shrinkage of the metal powder and secureconnectivity of the inner electrode layer.

However, according to an embodiment of the present invention, thesintering shrinkage of metal powder may be restrained by forming thenon-electrode region in the internal electrode layer and adjusting theratio of the non-electrode region. Also, the connectivity of the innerelectrode layer may be improved by adjusting the ratio of thenon-electrode region formed in the internal electrode layer.

Hereinafter, a method of manufacturing the multilayer ceramic capacitoraccording to an Example of the present invention will be described.

According to an Example of the present invention, a plurality of ceramicgreen sheets may be prepared. In order to manufacture the ceramic greensheets, slurry is fabricated by mixing ceramic powder, a binder, asolvent, and the like, and the slurry may be formed to have a sheet typehaving a thickness of several micrometers (μm) through a doctor blademethod. Each of the ceramic green sheets is then sintered to form eachdielectric layer 111 as shown in FIG. 2.

Next, conductive paste for an internal electrode is applied to theceramic green sheets to form internal electrode patterns. The internalelectrode patterns may be formed through screen printing or Gravureprinting.

Then, the ceramic green sheets having the internal electrode patternsformed thereon are laminated and pressurized in the lamination directionso as to be compressed. Accordingly, a ceramic laminate including theinternal electrode patterns formed thereon can be manufactured.

Thereafter, the ceramic laminate is cut into areas, each correspondingto one capacitor to form a chip. Here, the ceramic laminate may be cutsuch that the respective one ends of the internal electrode patterns arealternately exposed to sides thereof. Thereafter, the ceramic laminateas a chip may be fired to manufacture a ceramic element. As describedabove, firing may be performed under a reducing atmosphere. Also, thefiring may be performed by adjusting the heating rate. The heating ratemay range from 30□/60 s to 50□/60 s, but the present invention is notlimited thereto.

Then, external electrodes may be formed to cover the side faces of theceramic element and be electrically connected to the internal electrodelayers exposed to the side faces of the ceramic element. Thereafter, thesurface of the external electrodes may be plated with nickel, tin, orthe like.

According to an Example of the present invention, as described above,the ratio of the non-electrode region formed in the internal electrodelayer with respect to the electrode region may be between 0.1% and 10%.Accordingly, the connectivity of the inner electrode layer may beimproved and high capacitance may be implemented.

The multilayer ceramic capacitor according to an Example of the presentinvention was manufactured by adjusting the grain sizes of theceramic-based substance powder (BT, BaTiO₃ powder) and the metal powder(Ni) as shown in Table 1 below.

TABLE 1 Thickness of internal BT grain size:Ni electrode Electrode grainsize AN:AE (%) layer (μm) connectivity  1* 1:5 0.08%  0.41 86.3%  2  1:4.5 0.1% 0.44 90.2%  3 1:4 0.11%  0.42 92.1%  4* 1:6 0.57%  0.5590.2%  5 1:4 1.2% 0.39 90.8%  6 1:4 2.5% 0.47 92.9%  7 1:4 3.1% 0.4793.2%  8* 1:4 4.4% 0.53 92.7%  9 1:4 5.7% 0.50 94.3% 10 1:4 6.5% 0.4392.7% 11 1:4 7.6% 0.41 91.9%  12* 1:4 8.3% 0.52 90.3% 13 1:4 9.6% 0.3790.4% 14 1:4 9.9% 0.44 90.2%  15* 1:4 10.1%  0.45 89.3%  16* 1:4 11.3% 0.43 87.5% 17 1:3 5.3% 0.41 90.1% 18   1:3.5 6.2% 0.46 90.5% 19   1:3.54.3% 0.44 90.2% 20 1:4 6.5% 0.43 92.7% 21 1:4 2.5% 0.47 92.9%  22* 1:50.5% 0.45 82.2%  23* 1:5 5.2% 0.56 83.5%  24* 1:6 6.3% 0.61 81.2%

[Evaluation]

1. Area Ratio of Non-Electrode Region to Electrode Region of InternalElectrode (AN:AE(%))

The multilayer ceramic capacitor was cut in the length direction and animage of the cut cross section thereof was scanned by using an opticalmicroscope. An area of 10 μm×5 μm (width×length) was taken from theoptical image, and the area of the internal electrode layer, the area(AE) of the electrode region, and the area (AN) of the non-electroderegion were measured. The area of the internal electrode layer wasmeasured by excluding the gap G penetrating the internal electrodelayer. The area (AN) of the non-electrode region formed in the internalelectrode layer, through the optical image was measured, and the area(AE) of the electrode region was obtained and set by subtracting thearea (AN) of the non-electrode region from the area of the internalelectrode layer.

2. Thickness of Internal Electrode Layer

An actual length of the internal electrode layer was measured from theoptical image taken so as to have the size of 10 μm×5 μm (width×length),and a thickness of the internal electrode layer may be calculated as aratio of the area of the internal electrode layer with respect to theactual length of the internal electrode layer (internal electrode layerarea:actual length of the internal electrode layer). The actual lengthof the internal electrode layer was measured at a central portion of theinternal electrode layer, and in this case, the gap G formed betweenseparated portions of the internal electrode layer was excluded in themeasurement.

3. Connectivity of Internal Electrode Layer

The total length of the internal electrode layer was measured from theoptical image taken so as to have the size of 10 μm×5 μm (width×length).The total length of the internal electrode layer was measured as alength including the gap G formed between the separated portions of theinternal electrode layer. The connectivity of the internal electrodelayer was calculated as the ratio of the actual length of the internalelectrode layer to the total length of the internal electrode layer(actual length of the internal electrode layer:total length of theinternal electrode layer).

With reference to Table 1, test samples 22, 23, and 24 have a BT:Nigrain size ratio of 1:5 or less. In this case, it was determined thatthe grain size of the ceramic-based substance powder was extremelysmall, such that the shrinkage of the nickel powder was not restrainedand accordingly, the connectivity of the internal electrode layer wasless than 90%.

Referring to test sample 1, it showed that the BT:Ni grain size ratiowas 1:5, the ratio of AN:AE(%) was less than 0.1%, and thus theconnectivity of the internal electrode layer was less than 90%.

Referring to test samples 15 and 16, the BT:Ni grain size ratio was 1:4,but the ratio of AN:AE (%) exceeded 10%, such that the connectivity ofthe internal electrode layer was less than 90%.

Referring to test samples 4, 8, 23, and 24, when the thickness of theinternal electrode layer was 0.5 μm or greater, the connectivity of theinternal electrode layer was 90% or more, or 90% or less, regardless ofthe BT:Ni grain size ratio. Also, when the thickness of the internalelectrode layer is 0.5 μm or greater, it would be difficult to securethe number of laminations thereof, which leads to difficulty inimplementing high capacitance under the same conditions.

As set forth above, according to embodiments of the invention,connectivity of internal electrodes can be secured by controlling anarea ratio of a non-electrode region to an electrode region within theinternal electrode layers.

As the multilayer ceramic capacitor is reduced in size and highlymultilayered, the internal electrode layers become thinner. As theinternal electrode layers become thinner, the internal electrode layerscan be easily broken during sintering, such that securing connectivityof the internal electrode layer may be difficult. However, in anembodiment of the present invention, a non-electrode region can beformed within the internal electrode, and the area ratio of thenon-electrode region can be adjusted to secure the connectivity of theinternal electrode layer.

According to an embodiment of the present invention, a ceramic-basedsubstance powder could be disposed between metal grains during thesintering of the metal grains to thereby restrain a grain growth of themetal grains, and be trapped in the internal electrode layer to securethe connectivity of the internal electrode layer.

According to an embodiment of the present invention, a defect such as acrack, or the like, caused in the internal structure of the ceramicelectronic component may be prevented after firing.

According to an embodiment of the present invention, the capacitance ofthe multilayered ceramic capacitor can be secured.

While the present invention has been shown and described in connectionwith the embodiments, it will be apparent to those skilled in the artthat modifications and variations can be made without departing from thespirit and scope of the invention as defined by the appended claims.

What is claimed is:
 1. A ceramic electronic component comprising: aceramic element; and an internal electrode layer formed within theceramic element, having a thickness of 0.5 μm or less, and including anon-electrode region formed therein, wherein an area ratio of thenon-electrode region to an electrode region of the internal electrodelayer, in a cross section of the internal electrode layer is between0.1% and 10%, and the non-electrode region includes a ceramic component.2. The ceramic electronic component of claim 1, wherein a thickness ofthe internal electrode layer is 0.5 μm or less.
 3. The ceramicelectronic component of claim 1, wherein connectivity of the internalelectrode layer, as defined by a ratio of an actual length of theinternal electrode layer to the total length of the internal electrodelayer (actual length of the internal electrode layer:total length of theinternal electrode layer), is 90% or more.
 4. The ceramic electroniccomponent of claim 1, wherein the internal electrode layer is formed ofa conductive paste including metal powder and ceramic-based substancepowder whose grain size ratio to that of the metal powder exceeds 1:5.5. The ceramic electronic component of claim 1, wherein thenon-electrode region is formed by firing a conductive paste forming theinternal electrode layer at a heating rate ranging from 30° C./60 s to50° C./60 s.
 6. A ceramic electronic component comprising: a ceramicelement; and an internal electrode layer formed within the ceramicelement, wherein an area ratio of a non-electrode region to an electroderegion of the internal electrode layer, in a cross section of theinternal electrode layer is between 0.1% and 10%.
 7. The ceramicelectronic component of claim 6, wherein a thickness of the internalelectrode layer is 0.5 μm or less.
 8. The ceramic electronic componentof claim 6, wherein connectivity of the internal electrode layer, asdefined by a ratio of an actual length of the internal electrode layerto the total length of the internal electrode layer, is 90% or more. 9.The ceramic electronic component of claim 6, wherein the non-electroderegion is trapped at a metal particle interface of the internalelectrode layer.
 10. The ceramic electronic component of claim 6,wherein the non-electrode region includes ceramic-based substancepowder.
 11. The ceramic electronic component of claim 6, wherein theinternal electrode layer is formed of a conductive paste including metalpowder and ceramic-based substance powder whose grain size ratio to thatof the metal powder exceeds 1:5.
 12. The ceramic electronic component ofclaim 6, wherein the non-electrode region is formed by adjusting afiring temperature of a conductive paste forming the internal electrodelayer.